Method of performing skin-grafting operations and surgical instrument used therefor



Nov. 1 8, 1924i 1,516,071

L. APOLNT METHOD or' PERFORMING SKIN GRAFTING OPERATIONS AND SURGICAL INSQRUMENT USED THEREFOR Nov. 18, 1924. l 1,516,071

S. L. APOLANT f A METHOD `oF PERFORMING SKIN GRAFTING OPERATIONS AND SURGICAL INSTRUMENT USED THEREFOR Filed Nov. 2 192: s sheepS--sneer 2 l1# ga ATTORNEY Nov. 18, 1924.

APOLANT 192x 3 sheets-sheet 5 S. L. METHOD OF PERFORMING SKIN GRAFTING OPERATIONS AND SURGICAL INSTRUMENT USED THEREFOR Filed Nov. 2

. INVENTOR 5mn/ey L. Apu/mf 5 M ATTORNEY v Patented Nov. i8, 1924.

ld l

YES

STANLEY L. APOLANT, OF JERSEY CITY, NEW JERSEY.

METHOD OIF PERFORMING SKIN-GRAFTING OPERATIONS AND SURGICAL lINS'IIRUlVIIINl USED THEREFOR. v

Application filed November 2, 1921.

To @ZZ whom t may concern.'

Be it known that I, STANLEY L. AroLANT, a citizen of the United States, and resident of Jersey City, New Jersey, have invented certain newand useful Improvements in the Method of Performing Skin-@rafting Operations and Surgical Instruments Used Therefor, as set forth in the following specification.

This invention relates to an improved method of performing skin grafting operations and to a surgical instrument thought to be the first of its kind ever designed for stripping the epidermis from a portion of the body, of either a person or an animal, so that it can be used in a skin grafting operation.

Heretofore surgeons in performing grafting operations have been obliged to depend almost Wholly upon their skill or that of an assistant to hold the epidermis while they stripped the same by use of a hand-operated blade having a keen edge, an ordinary razor having often been used. This procedure at best is somewhat a crude one and often requires the service of two or more persons to skillfully and properly remove the desired amount of skin to be used for the graft. A difficulty usually encountered when performing grafting operations is that the epidermis has a tendency to curl which interferes with its handling and its proper placing on the wound of the patient.

Utilization of my improved method overcomes the above objections and my novel instrument provides means whereby operations of this nature can be performed more skillfully and quickly and in such manner that the thickness of epidermis removed can be very accurately predetermined. It also provides means for holding the epidermis taut both before and after it is removed from the body.

Among the principal objects of the invention are the improvement of the method of performing skin grafting operations. rlhe provision of means for mechanically driving a knife to remove the epidermis, and means for holdingv the skin taut, during the stripping operation; to provide a frame holder adapted to be removed from the instrument together with the portion of skin stripped; the provision of a flexible frame having angularly deposed needle points to Serial No. 512,183.

hold the epidermis in place, said frame belng adapted to be flexed or warped to fit the contour of the portion of the body of the patient on whom the graft is made; the provision of a frame holder having a transparent bottom to permit the surgeon to have a clear view of the knife blade While the epidermis is being stripped. The provision of means for adjusting the plane in which the knife blade operates to determine the thickness of the epidermis removed. The provision of a supporting frame for the'instrument which is open at thetop and bottom to permit a view of the movement of the knife. The provision of means for reciprocating the knife blade transversely and synchronously feeding it longitudinally. The provision of means for automatically discontinuing the feeding movement ofthe knife after it has completed the stripping operation. The provision of a guard ,adapted to permit the knife to move in'tially Without cutting into the epidermis While the instrument is in place and also adapted to bulge.

or hold the portion of epidermis to be removed in postion to be `subsequently stripped by the knife blade. The provision of needle frames having points of varying lengths to correspond to the different thicknesses of epidermis to be removed and the provision of a gage calibrated to correspond with the length of the needles carried by said frames to assist in setting the blade 'to y move in the proper plane. The provision of a frame having needles of polygonal cross-section. The provision of vertically adjustable means for guiding the knife blade. means arranged so that they can be readily removed from the frame of the machine to permit cleansing. The provision of means whereby the knife blade can be sprung into and out of position to permit its cleansing.

The provision of detachable guides and guards adapted to be removed for cleansing purposes. The provision of parts made of non-corrosive metal to improve the antiseptic character of the instrument. Another object is to combine and organize the various elements herein described so that they effectively perform their functions as set forth. Other objects will be apparent from the following description when read in connection with the accompanying drawings The provision of knife guidingk Cil Cil

which illustrate a novel form of surgical instrument by which the improved skin graf;- ing method can be practiced.

Fig. l is a longitudinal vertical section illustrating an instrument embodying novel features;

Fig. 2 is a transverse section of the instrument on the plane of line 2-2 of Fig. l;

Fig. 3 is an end elevation of the instrument viewed from the right hand end of Fig. l;

Fig. 4 is a side elevation viewed from the right hand; side of Fig. 2;

Fig. 5 is a. detail view of a clip for rot:==..; ing a guide;

Fig.. .f3 is an enlarged section through a portion` of theA flexible needle frame;

Figs. 7 and 8 are respectively plan and side views of a staple from which the needie points are formed.;

Fig. 9 is any isometric view of a detachable transparent needlev frame holder showing the needle frame in place;

Figs. 10 andv 11 are top views showing respectively the pilot nut guide and the head piece guide.

Figs. l2', 13, 14;, l5y and 16 are isometric views illustrating respectively the head piece, the pilot carriage, the guide yoke and details of the cross arm which support the knife blade in such manner that it can be reciprocated transversely in `one direction and fed horizontally.

Fig. l? is a view of the needle frame detached from the frame holder and holding the piece of stripped epidermis;

Fig. 118' is an isometric view of the main supporting frame of the instrument with all "parts removed except the detachable guard;

Fig. 19 is a detail of a gage used to determine the thick-ness of epidermis on the given portion yof the body.

Referring to the drawings the frame 2O isof rectangular formation having side walls'22 and 2-l and end walls 26 and 28, the wall 26 being l'iigher than the wall 28 to form an extended lip 30 for a purpose to be hereinafter' referred to.K The wallsl 22 and. 24'- are provided with sockets 32 and 811-, i6/and 38 to receive the ends of al guard e() formed? of side members Ll2 which are connected by a cross member del. The guard 4-.0 is so` shaped7 as best shown in Figs. l and 18,. that the members 4.2 are located substantial distance below the sides 22 and 24 of the main frame, and the cross bar lll of theguardis located a short distance forward of the end wall. 28. This arrangement permits they frame to be placed against a fleshy portion of the body so that the epidermis vwill bulge up between the lip 80 and the cross bar 44, as shown in Fig. l. The longitudinal bars l2 of the guard also bear against the body and these members with the Lemmi cross bar 44 and the extended lip 30 confine a substantially rectangular portion of epidermis.

Det-achably secured to the underside of the frame 20 is a needle frame holder adapted to hold a. flexible frame 6() having needles therein which enter the epidermis and hold it taut both before and after it is stripped. The frame holder 50 comprises a bottom plate 52 having side fianges 5st which frictionally engage the outer surfaces of the walls 22 and 2 of the main frame. rllhe plate 52 is provided with offset lips 5.6 in which is seated a sheet of plate glass or other transparent materia-l 58. it its forward end the plate 50 is bent downwardly and inwardly to form a lip 5l and at the opposite end a pair of ears 53 are struck down from the plate to hold the transparent slab 58 in place. The inner edges of the offset lips 56 are bevelled as shown at 57 to form dovetail ways for anecdle frame 60. This frame is rectangular and is open in the center as shown in Fig. 17. llt .is formed of sheet metal fol-ded on itself as shown in Fig. 6 and between the upper thickness 62 and the lower thickness 64e of the frame is interposed the body portions 66 of staplesy 68 which have depending pins or needle .points 70 formed thereon. The pins l Y() at the forwardv end of the needle frame G0 and' at the sides thereof are inclined downwardly and forwardly and the needlepoints at the rear end of the frame 6@ project downwardly and rearwardly. rlfhat is to say, the points on three sides of the frame project down at an angle in onefdirection and.` those on the fourth or rear end of the frame project in the opposite direction. rlihis disposition of the points is clearly shown in Fig. l. rl`he needles T0 are preferably of polygonal crosssection as illust-rated in Figs. 6 and 7, and they are conveniently formed by swaging them to the shape shown in5 ffull lines in Fig. 8 and subsequently bending them as indicated in dotted lines.

Needles of polygonal cross-section having points asV shown enter the skin more readily than round pointed ones and cause less tearing or stretching of the skin7 in other words they enter the flesh with what might be termed a cutting action. The angular disposition of the needlesv prevents the epidermis from slipping away from the needle frame both during thecutt-ing operation and after it is stripped from the body. lhen the needle frame is applied to the body it isa of course, held by the frame holder 50 which is in turn secured to the main frame 2O of the instrument. A forward and downward pressure is .first er:H erted yon the frame 2O whiclrforces the forwardly inclined points 7.0 into the epidermis. Downward pressure is then 4exerted over the rear portion of the frame which causes -f isn .'i A

'eteriea tof 1s guided. Ertending outifvaidi 1 5' I 1 N ,r f troni the lower eno. or each ekteiision i honi roble-l ne .nio

L; fr f tudinal moroni ciprocated transveA which conc/ts with thereof. that as the eed blade receives ing' reciprocated ic il() and ted longi screw. lif the k 1 i t is tnas con.

screw l nl is 'rotated the kniY i poinid movement, be-

rsely by the ecceir tndinally by said tite blade c Yt in a plane oblique to the axis ot vthe i screw instead or pf s ,udicular thereto shouf'n so as to malto diagonal or shearing cut.

The pilot carriage, head piece7 guide yoke and cross-arm are arranged with relation to one another so that the plane in which the knife blade operates can be varied to determine the thickness ot epidermis to be removed. This adjustment is accomplished by means of turning the adjusting screw so as to raise or lower the guide yoke which slidably carries the cross arm 82 which in turn supports the knife blade.

1n orc er to enable a surgeon, or operator, to set the blade to remove a predetermined thickness of the epidermisi l provide scalo markings 1Zl1 on the head-piece calibrated to correspond Vto diterent thicknesses. The graduations are nun'ibered to correspond with numbers which will be placed on di'l florent needle iframes 00 each'having needles l0 of proper length to be used in stripping diiierent thicknesses oi epidermis.

To illustrate, if it is desired to remove a strip of skim say El; of an inch thick, the thumb screw will he turned until the arrow 81 on the cross-arm S2 points to graduation number two on the scale 1417 and a number two needle 'frame 60 will be selected having needle points 'Z0 thereon which are slightly less than ci" an inch in length.

Lerenti The settino' or the knife blade ol course is determined by the thickness of the epiermis on the portion oi" the body troni which it is to be removed, and to assist the surgeon in measuring this thickness, l provide a gage 161, Fig'. 19, having a plurality or pins 162 secured thereto which are graudated in length and are numbered to correspond with the several needle trames 60. rlihe surgeon selects one or the points 1627 which in his iudgn'ient is approximately qual in length to the thickness of the epidermis on a portion of the body from which the skin is to be stripped. He then inserts this point and it it shows blood he inserts the nekt smaller point, it this one does not draw blood selects a needle train having points et a length corresponding substantially to the length or tie latter pin 162. llnese pins are numbered to make it a simple matter to choose a needle .iframe 60 having points or proper length for removing a given thickness oli epidermis. This is important because it ensures against the possibility oi" inserting' a needle Yframe having` points 70 oi such length that they will be struck by the knife blade 80 as it moved forward. ln other words, the numbered needle frames, the calibrations on the head piece and the markings on the 161 make the setting i :tieally automatic or fool-proof.

The lead screw 100 is reduced in diameter at one end 101i and fits in a suitable bearing aperture formed in the wall 28 of the main `frame, and above the portion 104 is located an oil hole 2l' to provide lubrication to this bearing. The opposite end 106 of the lead screw is also reduced in diameter and formed with a slot 108. The reduced end 10G is journalled in a removable bearing which is provided with a shank 1'2'2 which is threaded into a tapped hole 25 formed in the end wall 26 ci" the main trame. A suitable oil rhole 29 is formed in the end wall 20 and communicates with a registering' hole formed in the shank of the bearing' 170 to provide for lubrication of this bearing. A ilegible shaft is provided having a head 182 and a tongue 184 which enters the slot 108 to form a driving' connection with the lead screw 100. The flexible shaft is covered with a protective casing 185 which is clamped by a knurled head 186 having lugs 18.7 which engage with similar lugs 177 formed on the fitting' 170, the connection being similar in arrangement to the well known bayonet joint.

In operation a needle frame 60 having points ci the length desired is inserted into position under the transparent slab 58 of the needle frame holder, this holder is then rictionally secured to the under side of the main frame 20 by engagement of its flanges 54 with the side walls 22 and 211 of the lin.-

frame` The guard is then or has previously been secured in place by springing its ends into the sockets 32, 34, 35 and 38. The pilot carriage has previously been positioned, as shown in Fig. 1, and the blade 80 adjusted vertically to the desired plane by means of the adjusting screw 160. the accuracy of the setting being accomplished by means of the scale 141 and pointer 81, as will be understood.

The flexible shaft 180 having been previously connected to a suitable source of power, such as a dental motor, not shown. the instrument is given a downward and forward motion to bulge the epidermis and confine it between the front lip 30 of the main frame and the cross-bar 44 and side bars 42 of the guard 40 and to engage the forwardly extending pins 70. It is then given a slight backward movement to engage the oppositely extending pins firmly within the bulged portion of the epidermis. The power is now turned on which causes the feed screw 100 to rapidly rotate, causing the eccentric 90 to reciprocate the knife blade 80 through the cross-arm 82 to which it is connected as above described. It is to be noted that in the starting position the knife blade 8O is located to the rear of the cross-bar 44 of the guard. This permits the motion of the knife to get well under way and overcome inertia of the parts before it starts to out into the skin. By reason of the engagement of the nut portions 114 of the pilot carriage, the feed screw moves said pilot carriage and the associated parts including the guide yoke 150, head piece 14() and cross-arm 82 longitudinally and at the same time the knife blade is being reciprocated transversely. The feed screw moves the guide yoke at a uniform rate and reciprocates the knife synchronously therewith, the compound movement of the knife therefore effecting a continuous uniform cutting action. The pilot carriage is guided in its forward movement by the guide rods 120 and the upper guide grooves 111 formed inthe pilot carriage. At the end of its forward movement the pilot carriage comes opposite to the cut away portions 122 of the guide rods 120 which permits the spring 171 to force said pilot carriage upwardly and into contact with the under-surface of the head piece 140 which results in disengaging the pilot nuts 114 from the feed screw 100 so that the said pilot carriage can be quickly returned to its starting position. On the vreturn movement of the pilot carriage its lower grooves 113 ride on the guide rods 120. When the carriage is returned to the starting position its walls 112 come into register with the interrupted portions 124 of the guide rods and exertion of a slight pressure will bring it into position to engage the feed nuts with the feed screw 100 so that the operation may be repeated.

After a portion of epidermis hasv been stripped form the body, the instrument can `be lifted bodily and the frame holder can be slipped out of engagement with the main frame thereby greatly facilitating the handling' of the stripped piece of epidermis. The frame holder 5() which carries the needle frame and the strip of epidermis held thereby can be carried by the surgeon to a location near the patient to whom the graft is to be applied. The needle frame is then removed from the frame holder and said needle frame and the graft is applied to the wound of the patient and may be secured by means of bandages, surgeons tape or the like, it being remembered that the needle frame is formed of flexible material which permits it to readily conform to the shape of that portion of the body towhich the graft is made. After the graft begins to knit to the body of the patient the flexible needle frame is removed.

From the foregoing description it will bey clear to surgeons, physicians and others engaged in hospital work, that the method herein described marks an advance in this art whereby the epidermis can .be quickly stripped from the body with less harm to the person or animal from whom it is removed, than by former methods and that the graft is held taut after removal and hence can be more easily and skillfully applied to the wound of the patient. It is also clear that the utilization of a mechanically or power driven knife is a marked improvement over the primitive hand operated blade formerly used. The parts of thc instrument are arranged to permit af clear view of the movements of the knife andthe guard holds the portion of skin to be' stripped in place. The needle frame holdsl the skin taut and thereby permits the knife to make a clean cut without dragging the skin along with it, and also prevents the curling` of the graft after it is stripped.A The transparent bottom of the frame holder provides a flush slab against which the outer surface of the epidermis contacts and allows the surgeon to observe the progress of the cutting` operation, it being known to those skilled in the art that the epidermis is sufficiently transparent to permit the knife to show through. l

The instrument is so designed that there are comparatively few bolts or nuts used in its assemblage which would tend to gather dust and render the dismantling of the various parts for cleaning rather cumbersome. In dismantling the instrument it is merely necessary to revolve the guide rods 13() a half turn whereby the interrupted portions 132 Win be brought ini-,c `igiostioii to permit the removal of the head piece 140.l This ll U will permit the removal of the head piece, the' pilot carriage guide yoke and cross-arm after the knife blade has been sprung` outci engagement and removed from the arms S-flof the said cross-arm, therefore, all the parts can be readily cleansed. 'lo further render the instrument antiseptic the metal parts Will preferably be either heavily niekeled or else made entirely of non-corrosive mate,- rials.

rlfhough l have described With great particularity the steps in the method disclosed and the details of the embodiment of the invention herein shown, itis not to be ccnstrued that l am limited thereto7 as it is tllOnght that the present invention i entirely eiv advance in the art. tion of various known expediente mai. made to perform the functions hereiirdescribed Without departing from the invention as delined in the following elain'is.

What l claim is:

l. rllhe method of performing); a ski ing operation which consists in lioldmgij epidermis taut and strippingl it from a body and applying the taut epidern is to the body of the person on Whom thel graft is to be made.

2. The method of performing a skin graftin operation which consists in applyii j; means to keep. the epidermis taut on the boty of the person or animal While it is boing; stripped and stripping the epidermis from the body and applying the taut graft to a Wound on a patient.

3. The method of performing` a skin l{graftoperation which consists in lirst applying a guard and a needle frame to the body of the person or animal from Whom the skin is to be stripped tohold said skin tant t .d above the surrounding skin and strippin ine epidermis With mechanically driven knife and removing said needle frame and the taut `graft' held thereby and applying; it to a Wound on a body.

4. A surgical instrument having); a blade and means for moving` said blade and means on the instrument for ,Quidingz1 the blade below. the skin so as to remove from a body a flat piece of skin suitable for a graft.

5. A surgical instrument liavii knife blade. means secured to the instrument for holding' the epidermis in position. to be cnt bv said blade and means for moving; said knife blade to remove from a body a substantially flatstrip of epidermis suitable for a graft.

6,. Ar surgical instrument including blade9 mea for moving said blade to strip the epidermis, means for holding; the epidermisin position to be stripped and means the position of the blade can be a vary; the plane in which it moves to determine the, thickness of the strip of epidermis to removed.

7. A surgical instrument having reciprocating knife blade means for holding the epidermis in position to be cnt by said bl c and means for feeding,` 'd knife blade iu a direction substantially at right angles to the direction of its reciprocatory moven'ient to strip the epidermis from the body.

8. surgical instrument havinga mechanically driven. knife blade for stripping a por-- tion of the epidermis from a body and detachable needle-frame adapted to assist in holding the epidermis during the cutt movement of said blade and to hold the s; taut after it has been stripped from the body.

9. A fran'ie having a plurality of abonimly disp sod depending needle points at A ted to enter the epidermis and hold it taut. so that it can be readily handled in a graftine,` operation.

lO. A frame having a plurality of anfilarly disposed dependin' needle poi. ts adapted to enter the epidermis and hold ifv so that it can be readily handled in a graftin operation7 said frame beinil made of flexible material to permit it to yield to oonforn'i ll. A frame for holding a `graft lia-ving a plurality of needles of polygonal cross seetion secured thereto said needles being aref one group ranged in groups, the needles being' inclined in one direction and those 1 another group being inclined in the opposi direction thereto to prevent the from slipping away from the frame.

12. A surgical instrument having a mechanically driven blade for stripping; a graft of epidermis from a body. guiding` and supporting.` means for said blade and means associated therewith whereby the blade can be adjusted to va VVy the thickness of the graft removed.

l. A surgical instrun'ient havingv` a` mechanically driven blade for stripping' the epidermis from a body guiding; and supporting means for said blade and means associated therewith whereby the bladecan be adjusted to vary the thickness of epidermis to be removed. and means for holding the epidermis in place to be stripped by said blade.

14. A. surgical instrument for removing the epidermis having; a main frame which is open at the top and bottom, a pilot carriage movable .relatively to said frame, a knife blade movable with pilot carriage. a guide yoke associated with said pilot oarriage and arranged to permit a relative vertical movement betrveen it and said pilot carriage, feeding; means for movinggsaid pilot carriage longitudinally., and means for auto.- matically disengaging the pilot carriage llU from said feeding means at the-end oi its forward movement to permit said pilot carriage to be quickly reset to its starting position.

l5. A surgical instrument for removing the epidermis, having a main frame which is open at the top and bottom, a pilot carriage movable relatively to said frame, a knife blade movable with said pilot carriage, a guide yoke associated with said pilot carriage and arranged to permit a relative vertical movement between it and said pilot carriage, feeding means for moving said pilot carriage longitudinally, and means for automatically disengaging the pilot carriage from said feeding means at the end of its forward movement to permit said pilot carriage to be quickly re-set to its starting position, and a frame holder having a transparent wall said frame holder being detachably secured to said main frame, a frame slidably mounted in said frame holder having a plurality of needles secured thereto adapted to hold the portion ot epidermis stripped by said blade taut on said frame to prevent the graft from curling after it is stripped.

16. In a surgical instrument for stripping a graft of epidermis from a body, a frame holder adapted to be withdrawn from the instrument after the stripping operation, and a needle frame detachably secured to said frame holder and adapted to hold the epidermis taut to facilitate its handling in a grafting operation.

17. In a surgical instrument for stripping epidermis from a body, a frame holder having a transparent bottom wall said frame holder beingadapted to be withdrawn from the instrument after the stripping operation, and a flexible needle frame detachably secured to said frame holder and adapted to hold the epidermis taut to facilitate its handling in a grafting peration.

18. A surgical instrument for removing vthe epidermis, including a main frame, a

pilot carriage movable longitudinally thereof, a head piece slidable on said main frame and having guides which co-act with said pilot carriage, feedingl means for moving said pilot carriage longitudinally, a knife blade, means movable longitudinally with said pilot carriage for supporting said knife blade, means for reciprocating said blade transversely and means for releasing` said pilot carriage from said feeding means after it reaches the end of its stroke.

19. A surgical instrument for removing the epidermis, including a main frame having side and end walls and open at the top and bottom, a guard secured to said main frame adapted to be pressed against the body of the one from whom the epidermis is to be stripped to cause it to bulge up within the guard, a transversely reciprocating knife blade movable above said-guard, and means for Vfeeding said knife blade longitudinally to strip a portion of the epidern'iis above said guard.

20. A surgical instrument for removing a graft ot epidermis, including a hollow main frame open at top and bottom, a detachable needle frame holder slidaloly engaging` said main frame and having a transparent bottom, and a needle trame detachably secured to said frame holder adapted to hold thev epidermis taut before and after it is stripped from the body and a knife blade movable under said needle frame for severing the portion of epidermis held thereby.

2l. ln a device of the class described, a main frame, a holder slidably secured to said main frame having a transparent bottom, a needle frame slidably secured to said frame holder below the transparent bottom and having a plurality of epidermis engaging needle points secured thereto, a guard below said needle frame adapted to bear against the body 'from which the epidermis is being stripped and to assist in holding the portion being stripped in contact with said needle frame. y

22. ln a device of the class described, a main frame, a holder slidably secured to said main .frame having a transparent bottom, a needle frame slidably secured to said frame holder below the transparent bottom and having a plurality of epidermis engaging needle points secured thereto, a guard below said needle frame adapted to bear against the body from which the epidermis is being stripped and to assist in holding the portion being stripped in contact with said needle frame and a knife blade movable be tween said needle frame and said guard for stripping the epidermis from the body.

23. ln a device of the class described, a main supporting frame, a frame .holder detachably secured thereto and adapted to hold different needle iframes each having points of diiierent lengths corresponding respec ively to the thickness of epidermis to be moved, a guard mounted below said needle frame holder,a knife movable between said guard and said needle frame holder to strip the epidermis and means for adjusting said knife toward or away from the needle frame holder to control the thickness of the portion of epidermis removed.

24. In a device of the class described, main supporting tranne, a frame holder dctachably secured thereto and adapted to hold different needle frames cach having points of different lengths corresponding respectively to the thickness of epidermis to be removed. a guard mounted below said needle frame holder, a knife movable between said guard and said needle frame holder to strip the epidermis and means for adjusting said knife toward or away from 'llo A surgical instrument inclndii o' a main frame, carriage guides secured t ereto? a pilot carriage having trio sets of @guide TWays formed therein, one set beingl adpated to co-act with l guides during` the vance r aienient of said Geringe and the other set bein adapted to co-aet with saitguides during' the return movement of sanr carriage, a pilot nut secured to said carriage, a lead adapted to advance said can riage on ore set of .ai des. nieans for antoinatically lifting` said ci O'e to di the pilot nntfrom the feet at thee4 of the advance mover ent tbe pilot c rriage to permit its qnick retnrn? a guide yoke movable with said pilot carriage, means carried by said. froide yoke for snpporting` a knife blade, and means for reciprocating the knife carrying neans while the pilot carriage is advancing.

26. A surgical instrument including` a supporting frame, two sets of guide rods detachably secured thereto, a pilot guided by one set of guide rods, a head piece guided by the other set of rods and operatively connected with. saidI pilot carriage and arranged to be moved relatively thereto, a guide yoke slidable in said pilot riapre and connected by an adjustino' screw with said head piece7 a spring' carried by said guide yoke and arranged to exert a pressure on said pilot carriagej a cross-arm carried by said guide yoke, a knife blade carried by said cross-arm, a feed screw for moving said pilot carriage and means carried by said feed screw for moving` said cross-arm transversely while said pilot carriage moves it longitudinallv,

27. A snroical instrument including` a supporting; frame, pilot carriage movable longitudinally thereon, a knife blade, means operatively associated with said pilot carriagge for"supporting` said knife blade for transverse movement and means for synchronously feeding` said pilot carriage in one direction and moving said knife blade in another direction.

28. A surgical instrument including a supporting frame, a pilot carriage movable isieovi.

longitudinally thereoin a. knife blade; means operrtiifelj/ associated with said pilot carn riage for supporting` taitL knife blade for transverse movement and means for synchro nonsly feeding' said pilot ca age in one direction and isioving said knife blade in another directiona a head piece movable with said pilot carriage and means associated therewith and operatively connected with the knife blade supporting means arranged to adjust the position of the blade relatively to the supporting frane.

29. ln a device of the class described a vide rots detachu secured thereto, n ibei slidably ni tinted on said guide rods, said rods being` formed with interrupted portions to permit tlie removal of said sliding members for cleansing.

30. ln a device of the class described a mainv supporting frame, a lead screw mounted therein, a pilot carriage operatively engaging said lead screw, a knife blade, means movable with said pilot carriage for support/ing` said knife blade below said frame and means slidable on said lead screw and movable with said pilot carriage for reciprocating said knife blade.

3l. ln a device of the class described a main supporting frame, a lead screw inoiinted thereiin a removable bearing to permit the withdrawal of said lead screw for cleansing, and a flexible shaft for drivingsaid lead screw,

ln a device of the class described a reciprocating' cross-arm having` depending` portions with undercut tenons formed thereon and a detachable knife blade mortised to lit said tenons the depending portions of the cross-arm being` adapted to be sprung' into and ont of engagement with said mortises.

ln a device of the class described, a main supporting frame, a lead screw carried thereby, a pilot carriage co-acting with the lead screwi a knife blade5 means movable with said pilot carriage for supporting said blade, means for moving said blade transversely and means for breaking the driving` connection between said lead screw and said pilot carriage.

ln witness whereof, l have hereunto signed my naine.

STANLEY L. APOLANT Til 

